Automatic lapping machine



Aug. 28, 1962 Filed Dec. 21, 1959 A. F. LICHTENFELD AUTOMATIC LAPPING MACHINE 3 Sheets-Sheet 1 INVENTOR. fiz/qesp f-T /Cf/T/YFELU fz w 241 M.

Aug. 9 A. F. LICHTENFELD AUTOMATIC LAPPING MACHINE 3 Sheets-Sheet 2 Filed Dec. 21, 1959 INVENTOR.

flzfiwsa fi ZICHTENFELF .irromwx Aug. 28, 1962 A. F. LICHTENFELD 3,050,910

AUTOMATIC LAPPING MACHINE Filed Dec. 21, 1959 3 Sheets-Sheet 3 m la 6 INVENTOR.

1440250 F [It/ITEWFEL 0. BY

' rates ire ' ater ice 3,050,910 AUTOMATIC LAPPING MACHINE Alfred F. Lichtenfeld, Glenview, 111.; Hedwig Lichtenfeld,

e xecutrix of said Alfred F. Lichtenfeld, deceased, assignor of one-half to Harry J. Harris, Melrose Park, Ill.

Filed Dec. 21, 1959, Ser. No. 860,957 2 Claims. (Cl. 51129) My invention relates to improvements in automatic lapping machines.

My invention relates more particularly to a lapping machine of the type having a horizontally disposed rotary lapping plate or platform and means associated with the drive for said lapping plate for effecting an oscillatory or rotary movement of objects being face lapped upon the face or surface of the lapping plate.

The principal object of my invention is to provide an improved lapping machine having automatic means for moving work pieces back and forth over the lapping surface of the lapping plate while the same is being rotated.

A further object of my invention is to provide in combination with the above, means for pressing the surface of the work piece down against the lapping surface at a desired pressure.

A further object of the invention is to provide a lapping machine capable of operation in the manner described which can employ a plurality of work piece holding pots so that a greatly increased number of work pieces may be treated at the same time.

Other objects and advantages will be more apparent from the following description wherein reference is had to the accompanying drawings, upon which FIG. 1 is a side elevational view of my improved face lapping machine;

FIG. 2 is a plan 'view thereof;

FIG. 3 is a fragmentary plan view of approximately onefourth of the lapping plate and the mechanism associated with each quadrant of the same;

FIG. 4 is generally a cross-sectional view taken on the lines 44 of FIG. 3; and

FIG. 5 is a fragmentary section taken on the lines 5-5 of FIG. 2.

In the embodiment of the invention which I have chosen to illustrate and described the same, I have provided the usual lapping plate which in the present instance may be a cylindrical plate 18 that is comparatively thick in cross-section and mounted for rotation upon a comparatively large radial thrust bearing 12, the lapping plate being adapted to extend above the surface of the work table 14 approximately 1 inch, the plate being positioned in a medially spaced opening 16 in the work table 14. The combined radial and thrust bearing may be supported on a horizontal shelf 18 that is suspended below the work table 14, the table being preferably square and having at its four corners support legs 21) mounted upon foot pads 22. The driving motor 24 may be positioned upon a suitable shelf 26 supported by angle members 28 at its ends, the angle members 28 being connected between table legs 20.

The motor 24 may have a gear reducer 30 associated therewith to reduce the speed of the driven bevelled gear 32 to approximately 60 rpm. The bevelled gear 32 is in mesh with a similar gear 34 keyed to a vertically disposed drive shaft 36, the shaft 36 being journaled in suitable bearing mounts 38 and 40 supported by the upper shelf 18 and the motor shelf 26. The upper end of the drive shaft 36 is of course keyed to the lapping plate and may extend therethrough and have a ball bearing unit 42 eccentrically mounted on the top end of the same.

The ball bearing race 42, in the embodiment of the invention illustrated, has been shown as being offset approximately 1 inch so that as it rotates it will have a two inch outward travel from the inner to the outer edges of its eccentric circle. This thus effects approximately a two-inch movement of any object that engages the side of the same.

The lapping plate 10 that is used by users for face lapping work pieces 50, is of the type that has the parallel grooves 1% throughout its surface, providing square raised block formations 1% on the lapping surface of the plate in, and it is the action of these blocks as they wipe over the surface of a work piece covered with lapping compound that has the effect of producing the lapped surface desired on the work piece.

The lapping compounds are of course well known in the art, as well as the general features of the lapping surface of the plate 10, and further description will not be made, as it is only necessary to remember that any suitable or desirable lapping surface and any suitable or desirable lapping compound may be employed.

In using my improved machine, work pieces are placed in a lapping pot 6%, which may be in the nature of a metal ring of a desiredheight, the metal ring being guided in its action while the table is revolving by a pair of ball bearing rollers 62 and 64 which bear against the sides of the same, as best shown in FIG. 4. Each of the rollers 62 may be held by a support bracket 66 that extends above the same and may have a base portion 63 fastened on the table top 14 by screw members 70. Each of the rollers 64 may be carried between the jaws 72 of a U- shaped bracket 74 fastened to the forward end of a rod 76. The rod 76 is mounted in a hearing block 78, the rod 76 having a key slot 84 which receives a pin extension 82 of a thumb screw 84 that is screw-threadedly mounted in the bearing 78.

A coiled spring member 86 normally urges the roller support 74 inwardly toward the center of the lapping plate 10 so that, as best illustrated in FIGS. 2 and 3, each lapping pot 6b is held during its back and forth movement as caused by the rotation of the eccentric ball bearing 42, between the rollers 64 and 62. Since the roller 64 is spring mounted, it will yield and perm-it movement of the pot 6% from the full line position shown in HG. 3, to the dotted line position, at all times being yieldingly held by the spring pressed roller,64 which assumes the dotted line position shown in FIG. 3. The arrow on a radius about the center of the roller 62 shows the amount of "travel of the pot 60 and the arcuate path which it takes.

With this construction, when the lapping plate is being rotated at approximately r.p.rn., and the pots 60 are positioned as shown with work pieces in the same, rotation of the lapping plate will cause a rotation of the pots 66 by reason of their edge contact with the ball bearing race, the edge contact with the ball bearing rollers 62 and 64 permitting easy rotation of the pots.

Thus, while the work pieces are held against the face of the lapping plate by a weight W of desired amount placed over them in the pot 60, they may be rotated while they are moved back and forth through a segment of an arc, and at the same time the squares of the surface edge of the lapping plate are moving across them in a circular movement.

As can be seen from the arrangement of the guide rollers on FIG. 2, in the size lapping plate used four lapping pots may be simultaneously used, thus giving a maximum efficiency to the operation of the lapping plate. In the event a larger diameter lapping plate is used, it is possible to provide for the employment of more pots, the size and arrangement depending primarily on the diameter of the lapping plate being used.

From the above and foregoing description, it will be apparent to those skilled in the art that I have provided details shown and I do not wish to be limited in any particular; rather what I desire to secure and protect by Letters Patent of the United States is:

- 1. The combination with a rotatable lapping plate of means for holding a lapping pot on said plate and moving the same 'back and forth while said plate is rotating, said means comprising an eccentric unit on the lapping plate, a fixed lapping pot holding arm and a movable holding arm, said eccentric unit and said holding arms being adapted to engage a lapping pot at three points of contact. 2. The combination with a rotatable lapping plate of means for holding a lapping pot on said plate and moving the same back and forth while said plate is rotating, said means comprising an eccentric unit on the lapping plate, a fixed holding arm and a movable holding arm, said eccentric unit and said holding arms being adapted to engage a lapping pot at three points of contact, said fixed and said movable arms each having a roller for engagement with said lapping pot.

References Cited in the file of this patent Stead Apr. 28,1959 

